Fix load op to return the shape info as before when loading multiple blobs (#23166)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/23166
Changing the load op to take in shapes vector needs changes in lots of places (almost all usages of load op).
Instead this is a small and safe change where the behavior is unchanged if we are loading multiple blobs and when loading a single blob without shape information.
If you are loading just one blob and the shape information is provided, then this returns the right shape info back.
For all other cases, behavior is unchanged as before we introduced the issue.
This fixes the issue reported by Andrey in D16229465
Reviewed By: boryiingsu
Differential Revision: D16390551
fbshipit-source-id: 1055b481a7a9e83021209e59f38a7cc0b49003cf
